This invention generally relates to signal communication in remote signaling systems. More particularly, this invention relates to handling two types of signals using a receiver that operates, in part, as part of a remote keyless entry system.
Remote keyless entry systems for vehicles are well known. In typical arrangements a receiver is mounted on the vehicle that receives wireless communication signals from a portable, hand held transmitter used by an owner of the vehicle. Typical transmitters are embodied in a key fob having switches that are activated by the vehicle owner to indicate a desired action on the part of the remote keyless entry system, such as unlocking the doors or the trunk. The receivers typically used in such systems are amplitude shift keying (ASK) receivers. Such receivers are effective for receiving the radio frequency signals typically generated by transmitters in remote keyless entry systems.
ASK receivers are limited, however, to handling only certain types of signals. More recently, it has become desirable to incorporate multiple functions into fewer or the same number of components. These multiple functions now require receivers in such systems to handle more than one type of remotely generated signal. For example, it has been proposed to incorporate sensors on different components of a vehicle that will generate wireless communication signals indicating a sensed condition of the particular component. Because of the nature of such sensors and surrounding vehicle components, for example, the ASK receivers are not capable of adequately handling such signals so that useful information could be processed.
ASK receivers typically are programmed to enter a sleep mode except when an expected signal is present. This is accomplished through conventional squelch techniques. Therefore, typical strategies do not permit conventional receiver configurations to recognize various types of signals.
This invention provides a unique approach to enabling a receiver for a remote keyless entry system to also handle signals generated by one or more sensors placed on the vehicle to indicate a condition of a chosen component.